An optical transport network (Optical Transport Network, referred to as an OTN) is a transparent transport technology developed and formed to meet scheduling requirements of large capacity and coarse granularity on a backbone network layer. Signal types supported by the OTN become more and more abundant with continuous release of different versions of OTN standards. An old OTN standard (ITU-T G.709 Amendment1) defines three signal types: ODU1, ODU2, and ODU3, where bandwidths of the ODU1, ODU2, and ODU3 are 2.5 Gbit/s, 10 Gbit/s, and 40 Gbit/s respectively, and a tributary slot type supported by the ODU1, ODU2, and ODU3 is 2.5 Gbit/s. On the basis of the old OTN standard, an ODU1, ODU2, and ODU3 defined in a new OTN standard (ITU-T G.709 Amendment3 and G. sup43) also support a tributary slot type of 1.25 Gbit/s. In addition, the new OTN standard further proposes a new signal type that supports the tributary slot type of 1.25 Gbit/s, such as ODU0, ODU2e, ODU3e2, ODU4, and ODUflex with a variable bandwidth, and a new signal type ODU3e1 that supports the tributary slot type of 2.5 Gbit/s.
If an ODUj and ODUk are used to represent two signal types respectively, when the ODUj may be multiplexed to the ODUk and uses a tributary slot of the ODUk to transmit a signal, the ODUj is called a lower order ODU (Lower Order ODU, referred to as an LO ODU) and the ODUk is called a higher order ODU (Higher Order ODU, referred to as an HO ODU). For example, in the old OTN standard, the ODU1 may be multiplexed to the ODU2 and uses a tributary slot of the ODU2, where the type of the tributary slot is 2.5 Gbit/s, the ODU2 is a higher order ODU and the ODU1 is a lower order ODU. As compared with the old OTN standard, a higher order ODU of the same type in the new OTN standard supports more types of lower order ODUs and is compatible with the two tributary slot types, namely 2.5 Gbit/s and 1.25 Gbit/s. For example, when a higher order ODU is the ODU2, the ODU supports multiplexing of lower order ODUs such as ODU0, ODU1 and ODUflex; when a lower order ODU is the ODU1, the ODU2 supports signal transmission of the ODU1 in the two tributary slot types 2.5 Gbit/s and 1.25 Gbit/s.
An existing network has been deployed with an old device that complies with the old OTN standard and a new device that complies with the new OTN standard. Higher order ODU link capability of the old device is different from higher order ODU link capability of the new device. The new device is compatible with the higher order ODU link capability supported by the old device. However, ODU link capability supported by new devices of different types may vary. The old device does not support the newly-added higher order ODU link capability of the new device. After a higher order ODU link is established, in order to enable the higher order ODU link to be correctly used, nodes on the two ends of the higher order ODU link need to acquire the link capability. In the prior art, generally capability information of the higher order ODU link is manually configured on the nodes at the two ends of the higher order ODU link, so that the nodes use the higher order ODU link based on the link capability. The number of higher order ODU links on the network is very large. Therefore, a workload of manual configuration is heavy and efficiency is low.